How many ways can you purchase 2 CDs if there are 3 to choose from, 4 cassettes if there are 4 to choose from, and 2 DVDs if there are 5 to choose from?

1 Answer
Apr 22, 2016

Fot the first CD you have 3 choices. For the second there are only 2 choices left.


You can do any of these choices, so there are #2*3=6# possibilities to choose them in order . But the order doesn't matter. #2-1# is just as good as #1-2#. So you divide the number of possible ordered sequences by the possible orders. #6div2=3#
Written out this would be #1-2,1-3,2-3#

Cassettes: There's only one way -- you buy them all.

DVD: Almost the same as the cassettes: #(5*4)/2#